Polyol systems, which are to be reacted with polyisocyanates, are known for use in the manufacture of shoe soles. Typical of such systems are blends of polyester polyols and 1,4-butanediol. One commercially available polyester polyol has an hydroxyl number of about 54 and is produced from adipic acid, butanediol and ethylene glycol. When blended with butanediol in a weight ratio of 86:14, the resultant blend has a cloud point of about 72.degree. C. Thus, one problem with the abovenoted systems is that the polyol blend is not a single phase mixture unless it is heated to at least the cloud point.
The cloud point is the temperature at which a haze or cloudiness develops in the polyol blend when the blend is slowly cooled with stirring from a temperature sufficiently high to make the mixture a single phase. It is an object of this invention to develop a polyester polyol which when combined with butanediol or ethylene glycol will exhibit significantly lower cloud points than has been achieved with polyester polyols based on adipic acid, butanediol and ethylene glycol.